I called #6 into the bedroom and explained that I was tired. I also shared that the one thing that was making it impossible to sleep was his voice that I could hear down the hallway. I told him this just wasn't going to work. He said he was talking to #4. I told him that I needed, for his safety, to keep him on the same floor of the house as me but were there other options of places upstairs where he could sleep.
When I got up for the day, I went down the hallway and threw in a load of laundry. I peeked across the hall into the bathroom and found one blanket and a pillow on the floor but no boy. I walked down the hallway, and there he was, snoozing soundly in his bed.
Gotta love those natural consequences!